1. Field of the Invention
This invention relates to a method of heating hot beverage serving urns and methods of keeping the hot beverage hot while within the urn.
2. Discussion of the Prior Art
Coffee urns of the type into which coffee is directly brewed at a brewing location and then moved to a serving location where the coffee, tea or other brewed beverage is served from a serving faucet, or spigot, are well known in the art of brewing and serving of hot coffee and tea. In order to keep the brewed beverage at the desired temperature at which it was freshly brewed, it is generally preferable to fill the urn with the hot beverage. Such urns come in different sizes such as one, one and one half, two and three gallons.
A problem with such serving urns is that often the coffee becomes too cool for good quality before the urn is depleted. In order to overcome this problem, it is known to an internal or external electrically powered heating element. It is also known to insulate the urn to reduce heat loss after the urn is filled with beverage. Heat loss occurs by way of radiation. Heat loss also occurs by direct loss when hot beverage is served from the dispensing urn, and the heat of the beverage is physically removed from the beverage. As a consequence of such heat loss, the serving time during which the beverage is still above the minimum serving temperature, for best flavor and desirability, is only approximately one to one and one half hours if the dispensing urn is initially filled to capacity. If the urn is not filled to capacity but is only half filled, for instance, then the serving time may be reduced proportionately with the reduction in percentage of full capacity. Part of the problem is that the NSF and brewer industry standards require the use of stainless steel that has a relatively high rate of heat transfer.
The known ways of overcoming this serving time limitation include not moving the serving urn from the location at which it is brewed and keeping it on an external hot plate or other external heating element at the brewing location. This approach disadvantageously ties up the brewing location such that other urns cannot be filled, and, of course, demands that servers return to the original brewing location to serve the beverage into a smaller serving container such as a carafe or into a cup for direct service.
Alternatively, it is know to move the urn closer to the serving location and then place it on an electrical hot plate at another location or, to provide the urn with an internal heating element that is plugged into an AC power outlet for receipt of electrical power at a remote location in order to maintain the temperature of the beverage at the desired temperature. The need for a source of electrical power, at hand, to power the hot plate or internal heating element, and is not convenient when it is desired to locate the urn in a central location away from an AC power wall outlet. Even if there are floor outlets, if the urn is placed on a table, then a power cord must come up from the floor and rest upon table to reach the hot plate or the connection to the urn, itself, in the case of an internal, electrically powered heating element.
Another problem with electrical heaters is that controlling the heating element requires a thermo-mechanical or electronic thermostat to insure that not to much heat is added to the urn. Too much heat due to power surges or improper calibration can result in reduction of the beverage due to evaporation and overheating of the flavor elements of the brew. Both of these conditions may undesirably alter the flavor and aroma of the beverage being served. Coffee that is served too hot can also create risk of scalding and potential civil liability to the server. Likewise, there may be an increased risk of liability associated with electrical power cords lying on a service floor and hot plates and continuously electrically powered or thermostatically controlled electrically powered heating elements.
As a consequence of the problems associated with electrically powered heating elements and hot plates, noted above, and also with the non-heated, insulated urn which does not keep the beverage above a minimum desired temperature for longer an 1-2 hours, particularly in the case of less than a full brew capacity filling the urn, there is an unfulfilled need in the market of commercial coffee brewers and serving systems and the like for methods for maintaining temperature of hot beverages within a serving urn that overcomes these limitations and disadvantages.
In accordance with the present invention, the problems noted above that are associated with the failure of non-heated urns to maintain heated beverages above a minimum time period desired by the commercial brewer user industry and the disadvantages associated with electrically powered hot plates or internal electrical heating elements, are overcome.
This objective is achieved in part by providing a method of maintaining temperature of a hot beverage within a beverage urn by performing the steps of steps of inserting a hot beverage within an urn body having an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack having a zeolite-like material that is one of (a) hydrated salt and a eutectic salt, heating the heat pack by adding water vapor to the zeolite-like material to initiate an exothermic phase change reaction, placing the heat pack into the compartment in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner; moving the urn to a serving location spaced from the external source of power; and transferring heat from the heat pack to the liner and any beverage contained within the liner at the serving location.
The objective is also obtained in part by providing a method of maintaining temperature of a hot beverage within a beverage urn, comprising the steps of inserting a hot beverage within an urn body having an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack formed of a composite ceramic sandwich having an interior ceramic core with a relatively high rate of heat transfer contained within an outer envelope layer of ceramic of relatively low rate of heat transfer; heating the interior ceramic core, placing the heat pack into the compartment in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner, moving the urn to a serving location spaced from the external source of power; and transferring heat from the heat pack to the liner and any beverage contained within the liner at the serving location.
Also, the objective is achieved by providing a method of maintaining temperature of a hot beverage within a beverage urn by performance of the steps of directly brewing a hot beverage into an urn body having an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack, placing a heat pack within the compartment in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner, heating the heat pack during a brew cycle of the brewer with a heat pack heating apparatus associated with the brewer, moving the urn to a serving location spaced from the external source of power; and transferring heat from the heat pack to the liner and any beverage contained within the liner at the serving location.
Additionally, the objective is obtained by providing a method of maintaining temperature of a hot beverage within a beverage urn by performing the steps of inserting a hot beverage within an urn body having an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack having a zeolite-like material that is one of (a) hydrated salt and a eutectic salt, heating the heat pack by adding water vapor to the zeolite-like material to initiate an exothermic phase change reaction, placing the heat pack into the compartment in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner; moving the urn to a serving location spaced from the external source of power, and transferring heat from the heat pack to the liner and any beverage contained within the liner at the serving location.
Further, the objective is obtained partly by providing method of maintaining temperature of a hot beverage within a beverage urn composed of the steps of inserting a hot beverage within an urn body having an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack formed of a composite ceramic sandwich having an interior ceramic core with a relatively high rate of heat transfer contained within an outer envelope layer of ceramic of relatively low rate of heat transfer; heating the interior ceramic core, placing the heat pack into the compartment in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner, moving the urn to a serving location spaced from the external source of power; and transferring heat from the heat pack to the liner and any beverage contained within the liner at the serving location.
Moreover, the objective is acquired by providing a method of maintaining temperature of a hot beverage within a beverage urn having the steps of directly brewing a hot beverage into an urn body having an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack, placing a heat pack within the compartment in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner; heating the heat pack during a brew cycle of the brewer with a heat pack heating apparatus associated with the brewer, moving the urn to a serving location spaced from the external source of power, and transferring heat from the heat pack to the liner and any beverage contained within the liner at the serving location.